74 Mr. H. J. Carter on the Sponger 



this is the living species that I have had under observation), 

 that Lacaze-Duthiers's figures (viz. 1-8, which are the prin- 

 cipal ilkistrations to Schmidt's description) were made during 

 life, and that Schmidt's own (viz. 9-13 inclusive) have the 

 contracted forms presented to Schmidt in the preserved speci- 

 men. 



Although Schmidt's section of the two papillae (fig. 12), re- 

 presenting the sarcodal columns in connexion respectively with 

 large canals below them, while the latter, again, are stated to 

 open on the surface by several little orifices between the co- 

 lumns (that is to say, sieve-like), is exactly like the stmcture 

 of the papilliform inhalant area of Grayella (see my figures, 

 /. c), yet in fig. 11 Schmidt represents an osculum, or large 

 excretory orifice, in the centre of the marginated disk of a 

 papilla, in addition to the sieve-like group of little pores close ■ 

 to the margin. If Schmidt be right in considering this an 

 osculum and the group of smaller apertures " inhalant pores," 

 then we must infer that the osculum is in connexion with its 

 own excretory canal, and that the pores have their own inha- 

 lant canals or canal beside it, in which case this is an instance 

 of the combination in one papilla of both organs, viz. the ex- 

 current and incurrent system of canals respectively — a possible 

 combination which I do not deny, but of which I have seen 

 no example either in Grayella or Cliona. 



I say " if right," because Schmidt's observations having 

 been made on a preserved specimen, his distinction of excur- 

 rent and incurrent apertures must be made from resemblances, 

 as, I think, is stated in his description. 



Now, if Lacaze-Duthiers's fig. 8, representing a mammilli- 

 form eminence terminated by a single large orifice, be viewed 

 as an excurrent organ, and the fringed papillae respectively 

 with their sieve-like orifices as inhalant areee, then the analogy 

 between Grayella and Osculina becomes very strong. But in 

 Schmidt's description, as before stated, they are all alike re- 

 garded as excretory ; there is no part illustrative of the great 

 inhalant system but the little insignificant group of orifices 

 placed on one side of the disk of a papilla otherwise devoted 

 to the excretory system, as above mentioned. 



My impression of such orifices is that, for the most part, 

 excretory openings are large, single, and simple, and that it 

 is the oral ones which are tentaculated, fringed, or otherwise 

 ornamented with useful appendages. In Actinia and Hydra, 

 where there is but one orifice for both purposes, it is orna- 

 mented ; but certainly in the Polyzoa and Ascidia?, where 

 there are two, it is the oral, and not the anal, orifice which is 

 thus complicated. Hence, from analogy, I should be inclined 



